A certain number of artisans can complete a shoe fabrication consignment in 16 days. 8 additional artisans had to be deployed for the same consignment and together they completed it in 4 days less than the earlier estimate. The number of artisans initially employed was
Aptitude
Chain Rule
Difficulty: Medium
Choose an option
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A18
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B20
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C24
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DNone of these
Answer
Correct Answer: 24
Explanation
### Concept & Work Equivalence Principle
When the total amount of work remains constant, the number of workers is inversely proportional to the number of days taken.
$$ M_1 \times D_1 = M_2 \times D_2 $$
### Step-by-Step Solution
1. **Define the initial state:** Let the initial number of artisans be $x$. They take 16 days.
- Total Work = $x \times 16$
2. **Define the new state:** 8 additional artisans are deployed, making the total number $(x + 8)$. They complete the work in 4 days less, meaning it takes $16 - 4 = 12$ days.
- Total Work = $(x + 8) \times 12$
3. **Equate the work:**
- $16x = 12(x + 8)$
4. **Solve for $x$:**
- $16x = 12x + 96$
- $4x = 96$
- $x = 24$
### Exam Strategy & Shortcut
Use the ratio method. The ratio of days taken is $16 : 12$, which simplifies to $4 : 3$.
Since days and workers are inversely proportional, the ratio of workers must be $3 : 4$.
The difference in the ratio is 1 unit, which corresponds to the 8 additional artisans.
Initial workers = 3 units = $3 \times 8 = 24$.
### Common Pitfall
Misinterpreting "4 days less" as completing the work in exactly 4 days. Always subtract the saved days from the original estimate ($16 - 4 = 12$).
### Final Answer
Therefore, the correct answer is **24**.